gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 /* The default branch cost is 1.  */
  23 #ifndef BRANCH_COST
  24 #define BRANCH_COST 1
  25 #endif
  26
  27 /* Macros to access the slots of a QUEUED rtx.
  28    Here rather than in rtl.h because only the expansion pass
  29    should ever encounter a QUEUED.  */
  30
  31 /* The variable for which an increment is queued.  */
  32 #define QUEUED_VAR(P) XEXP (P, 0)
  33 /* If the increment has been emitted, this is the insn
  34    that does the increment.  It is zero before the increment is emitted.
  35    If more than one insn is emitted, this is the first insn.  */
  36 #define QUEUED_INSN(P) XEXP (P, 1)
  37 /* If a pre-increment copy has been generated, this is the copy
  38    (it is a temporary reg).  Zero if no copy made yet.  */
  39 #define QUEUED_COPY(P) XEXP (P, 2)
  40 /* This is the body to use for the insn to do the increment.
  41    It is used to emit the increment.  */
  42 #define QUEUED_BODY(P) XEXP (P, 3)
  43 /* Next QUEUED in the queue.  */
  44 #define QUEUED_NEXT(P) XEXP (P, 4)
  45
  46 /* This is the 4th arg to `expand_expr'.
  47    EXPAND_STACK_PARM means we are possibly expanding a call param onto
  48    the stack.  Choosing a value of 2 isn't special;  It just allows
  49    some code optimization in store_expr.
  50    EXPAND_SUM means it is ok to return a PLUS rtx or MULT rtx.
  51    EXPAND_INITIALIZER is similar but also record any labels on forced_labels.
  52    EXPAND_CONST_ADDRESS means it is ok to return a MEM whose address
  53     is a constant that is not a legitimate address.
  54    EXPAND_WRITE means we are only going to write to the resulting rtx.
  55    EXPAND_MEMORY means we are interested in a memory result, even if
  56     the memory is constant and we could have propagated a constant value.  */
  57 enum expand_modifier {EXPAND_NORMAL = 0, EXPAND_STACK_PARM = 2, EXPAND_SUM,
  58                       EXPAND_CONST_ADDRESS, EXPAND_INITIALIZER, EXPAND_WRITE,
  59                       EXPAND_MEMORY};
  60
  61 /* Prevent the compiler from deferring stack pops.  See
  62    inhibit_defer_pop for more information.  */
  63 #define NO_DEFER_POP (inhibit_defer_pop += 1)
  64
  65 /* Allow the compiler to defer stack pops.  See inhibit_defer_pop for
  66    more information.  */
  67 #define OK_DEFER_POP (inhibit_defer_pop -= 1)
  68 \f
  69 /* If a memory-to-memory move would take MOVE_RATIO or more simple
  70    move-instruction sequences, we will do a movstr or libcall instead.  */
  71
  72 #ifndef MOVE_RATIO
  73 #if defined (HAVE_movstrqi) || defined (HAVE_movstrhi) || defined (HAVE_movstrsi) || defined (HAVE_movstrdi) || defined (HAVE_movstrti)
  74 #define MOVE_RATIO 2
  75 #else
  76 /* If we are optimizing for space (-Os), cut down the default move ratio.  */
  77 #define MOVE_RATIO (optimize_size ? 3 : 15)
  78 #endif
  79 #endif
  80
  81 /* If a clear memory operation would take CLEAR_RATIO or more simple
  82    move-instruction sequences, we will do a clrstr or libcall instead.  */
  83
  84 #ifndef CLEAR_RATIO
  85 #if defined (HAVE_clrstrqi) || defined (HAVE_clrstrhi) || defined (HAVE_clrstrsi) || defined (HAVE_clrstrdi) || defined (HAVE_clrstrti)
  86 #define CLEAR_RATIO 2
  87 #else
  88 /* If we are optimizing for space, cut down the default clear ratio.  */
  89 #define CLEAR_RATIO (optimize_size ? 3 : 15)
  90 #endif
  91 #endif
  92 \f
  93 enum direction {none, upward, downward};
  94
  95 /* Structure to record the size of a sequence of arguments
  96    as the sum of a tree-expression and a constant.  This structure is
  97    also used to store offsets from the stack, which might be negative,
  98    so the variable part must be ssizetype, not sizetype.  */
  99
 100 struct args_size
 101 {
 102   HOST_WIDE_INT constant;
 103   tree var;
 104 };
 105
 106 /* Package up various arg related fields of struct args for
 107    locate_and_pad_parm.  */
 108 struct locate_and_pad_arg_data
 109 {
 110   /* Size of this argument on the stack, rounded up for any padding it
 111      gets.  If REG_PARM_STACK_SPACE is defined, then register parms are
 112      counted here, otherwise they aren't.  */
 113   struct args_size size;
 114   /* Offset of this argument from beginning of stack-args.  */
 115   struct args_size offset;
 116   /* Offset to the start of the stack slot.  Different from OFFSET
 117      if this arg pads downward.  */
 118   struct args_size slot_offset;
 119   /* The amount that the stack pointer needs to be adjusted to
 120      force alignment for the next argument.  */
 121   struct args_size alignment_pad;
 122   /* Which way we should pad this arg.  */
 123   enum direction where_pad;
 124 };
 125
 126 /* Add the value of the tree INC to the `struct args_size' TO.  */
 127
 128 #define ADD_PARM_SIZE(TO, INC)                          \
 129 do {                                                    \
 130   tree inc = (INC);                                     \
 131   if (host_integerp (inc, 0))                           \
 132     (TO).constant += tree_low_cst (inc, 0);             \
 133   else if ((TO).var == 0)                               \
 134     (TO).var = convert (ssizetype, inc);                \
 135   else                                                  \
 136     (TO).var = size_binop (PLUS_EXPR, (TO).var,         \
 137                            convert (ssizetype, inc));   \
 138 } while (0)
 139
 140 #define SUB_PARM_SIZE(TO, DEC)                          \
 141 do {                                                    \
 142   tree dec = (DEC);                                     \
 143   if (host_integerp (dec, 0))                           \
 144     (TO).constant -= tree_low_cst (dec, 0);             \
 145   else if ((TO).var == 0)                               \
 146     (TO).var = size_binop (MINUS_EXPR, ssize_int (0),   \
 147                            convert (ssizetype, dec));   \
 148   else                                                  \
 149     (TO).var = size_binop (MINUS_EXPR, (TO).var,        \
 150                            convert (ssizetype, dec));   \
 151 } while (0)
 152
 153 /* Convert the implicit sum in a `struct args_size' into a tree
 154    of type ssizetype.  */
 155 #define ARGS_SIZE_TREE(SIZE)                                    \
 156 ((SIZE).var == 0 ? ssize_int ((SIZE).constant)                  \
 157  : size_binop (PLUS_EXPR, convert (ssizetype, (SIZE).var),      \
 158                ssize_int ((SIZE).constant)))
 159
 160 /* Convert the implicit sum in a `struct args_size' into an rtx.  */
 161 #define ARGS_SIZE_RTX(SIZE)                                     \
 162 ((SIZE).var == 0 ? GEN_INT ((SIZE).constant)                    \
 163  : expand_expr (ARGS_SIZE_TREE (SIZE), NULL_RTX, VOIDmode, 0))
 164
 165 /* Supply a default definition for FUNCTION_ARG_PADDING:
 166    usually pad upward, but pad short args downward on
 167    big-endian machines.  */
 168
 169 #define DEFAULT_FUNCTION_ARG_PADDING(MODE, TYPE)                        \
 170   (! BYTES_BIG_ENDIAN                                                   \
 171    ? upward                                                             \
 172    : (((MODE) == BLKmode                                                \
 173        ? ((TYPE) && TREE_CODE (TYPE_SIZE (TYPE)) == INTEGER_CST         \
 174           && int_size_in_bytes (TYPE) < (PARM_BOUNDARY / BITS_PER_UNIT)) \
 175        : GET_MODE_BITSIZE (MODE) < PARM_BOUNDARY)                       \
 176       ? downward : upward))
 177
 178 #ifndef FUNCTION_ARG_PADDING
 179 #define FUNCTION_ARG_PADDING(MODE, TYPE)        \
 180   DEFAULT_FUNCTION_ARG_PADDING ((MODE), (TYPE))
 181 #endif
 182
 183 /* Supply a default definition for FUNCTION_ARG_BOUNDARY.  Normally, we let
 184    FUNCTION_ARG_PADDING, which also pads the length, handle any needed
 185    alignment.  */
 186
 187 #ifndef FUNCTION_ARG_BOUNDARY
 188 #define FUNCTION_ARG_BOUNDARY(MODE, TYPE)       PARM_BOUNDARY
 189 #endif
 190
 191 tree split_complex_types (tree);
 192 tree split_complex_values (tree);
 193
 194 /* Nonzero if we do not know how to pass TYPE solely in registers.  */
 195 extern bool default_must_pass_in_stack (enum machine_mode, tree);
 196 #ifndef MUST_PASS_IN_STACK
 197 #define MUST_PASS_IN_STACK(MODE,TYPE) default_must_pass_in_stack(MODE, TYPE)
 198 #endif
 199
 200 /* Supply a default definition of STACK_SAVEAREA_MODE for emit_stack_save.
 201    Normally move_insn, so Pmode stack pointer.  */
 202
 203 #ifndef STACK_SAVEAREA_MODE
 204 #define STACK_SAVEAREA_MODE(LEVEL) Pmode
 205 #endif
 206
 207 /* Supply a default definition of STACK_SIZE_MODE for
 208    allocate_dynamic_stack_space.  Normally PLUS/MINUS, so word_mode.  */
 209
 210 #ifndef STACK_SIZE_MODE
 211 #define STACK_SIZE_MODE word_mode
 212 #endif
 213
 214 /* Provide default values for the macros controlling stack checking.  */
 215
 216 #ifndef STACK_CHECK_BUILTIN
 217 #define STACK_CHECK_BUILTIN 0
 218 #endif
 219
 220 /* The default interval is one page.  */
 221 #ifndef STACK_CHECK_PROBE_INTERVAL
 222 #define STACK_CHECK_PROBE_INTERVAL 4096
 223 #endif
 224
 225 /* The default is to do a store into the stack.  */
 226 #ifndef STACK_CHECK_PROBE_LOAD
 227 #define STACK_CHECK_PROBE_LOAD 0
 228 #endif
 229
 230 /* This value is arbitrary, but should be sufficient for most machines.  */
 231 #ifndef STACK_CHECK_PROTECT
 232 #define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
 233 #endif
 234
 235 /* Make the maximum frame size be the largest we can and still only need
 236    one probe per function.  */
 237 #ifndef STACK_CHECK_MAX_FRAME_SIZE
 238 #define STACK_CHECK_MAX_FRAME_SIZE \
 239   (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
 240 #endif
 241
 242 /* This is arbitrary, but should be large enough everywhere.  */
 243 #ifndef STACK_CHECK_FIXED_FRAME_SIZE
 244 #define STACK_CHECK_FIXED_FRAME_SIZE (4 * UNITS_PER_WORD)
 245 #endif
 246
 247 /* Provide a reasonable default for the maximum size of an object to
 248    allocate in the fixed frame.  We may need to be able to make this
 249    controllable by the user at some point.  */
 250 #ifndef STACK_CHECK_MAX_VAR_SIZE
 251 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
 252 #endif
 253 \f
 254 /* Functions from optabs.c, commonly used, and without need for the optabs
 255    tables:  */
 256
 257 /* Passed to expand_simple_binop and expand_binop to say which options
 258    to try to use if the requested operation can't be open-coded on the
 259    requisite mode.  Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using
 260    a library call.  Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try
 261    using a wider mode.  OPTAB_MUST_WIDEN says try widening and don't
 262    try anything else.  */
 263
 264 enum optab_methods
 265 {
 266   OPTAB_DIRECT,
 267   OPTAB_LIB,
 268   OPTAB_WIDEN,
 269   OPTAB_LIB_WIDEN,
 270   OPTAB_MUST_WIDEN
 271 };
 272
 273 /* Generate code for a simple binary or unary operation.  "Simple" in
 274    this case means "can be unambiguously described by a (mode, code)
 275    pair and mapped to a single optab."  */
 276 extern rtx expand_simple_binop (enum machine_mode, enum rtx_code, rtx,
 277                                 rtx, rtx, int, enum optab_methods);
 278 extern rtx expand_simple_unop (enum machine_mode, enum rtx_code, rtx, rtx,
 279                                int);
 280
 281 /* Report whether the machine description contains an insn which can
 282    perform the operation described by CODE and MODE.  */
 283 extern int have_insn_for (enum rtx_code, enum machine_mode);
 284
 285 /* Emit code to make a call to a constant function or a library call.  */
 286 extern void emit_libcall_block (rtx, rtx, rtx, rtx);
 287
 288 /* Create but don't emit one rtl instruction to perform certain operations.
 289    Modes must match; operands must meet the operation's predicates.
 290    Likewise for subtraction and for just copying.
 291    These do not call protect_from_queue; caller must do so.  */
 292 extern rtx gen_add2_insn (rtx, rtx);
 293 extern rtx gen_add3_insn (rtx, rtx, rtx);
 294 extern rtx gen_sub2_insn (rtx, rtx);
 295 extern rtx gen_sub3_insn (rtx, rtx, rtx);
 296 extern rtx gen_move_insn (rtx, rtx);
 297 extern int have_add2_insn (rtx, rtx);
 298 extern int have_sub2_insn (rtx, rtx);
 299
 300 /* Emit a pair of rtl insns to compare two rtx's and to jump
 301    to a label if the comparison is true.  */
 302 extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 303                                      enum machine_mode, int, rtx);
 304
 305 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 306 extern void emit_indirect_jump (rtx);
 307
 308 #ifdef HAVE_conditional_move
 309 /* Emit a conditional move operation.  */
 310 rtx emit_conditional_move (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 311                            rtx, rtx, enum machine_mode, int);
 312
 313 /* Return nonzero if the conditional move is supported.  */
 314 int can_conditionally_move_p (enum machine_mode mode);
 315
 316 #endif
 317 rtx emit_conditional_add (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 318                           rtx, rtx, enum machine_mode, int);
 319
 320 \f
 321 /* Functions from expmed.c:  */
 322
 323 /* Arguments MODE, RTX: return an rtx for the negation of that value.
 324    May emit insns.  */
 325 extern rtx negate_rtx (enum machine_mode, rtx);
 326
 327 /* Expand a logical AND operation.  */
 328 extern rtx expand_and (enum machine_mode, rtx, rtx, rtx);
 329
 330 /* Emit a store-flag operation.  */
 331 extern rtx emit_store_flag (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 332                             int, int);
 333
 334 /* Like emit_store_flag, but always succeeds.  */
 335 extern rtx emit_store_flag_force (rtx, enum rtx_code, rtx, rtx,
 336                                   enum machine_mode, int, int);
 337
 338 /* Functions from loop.c:  */
 339
 340 /* Given an insn and condition, return a canonical description of
 341    the test being made.  */
 342 extern rtx canonicalize_condition (rtx, rtx, int, rtx *, rtx, int);
 343
 344 /* Given a JUMP_INSN, return a canonical description of the test
 345    being made.  */
 346 extern rtx get_condition (rtx, rtx *, int);
 347
 348 /* Generate a conditional trap instruction.  */
 349 extern rtx gen_cond_trap (enum rtx_code, rtx, rtx, rtx);
 350 \f
 351 /* Functions from builtins.c:  */
 352 extern rtx expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 353 extern tree std_build_builtin_va_list (void);
 354 extern void std_expand_builtin_va_start (tree, rtx);
 355 extern rtx std_expand_builtin_va_arg (tree, tree);
 356 extern rtx expand_builtin_va_arg (tree, tree);
 357 extern rtx default_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 358 extern void expand_builtin_setjmp_setup (rtx, rtx);
 359 extern void expand_builtin_setjmp_receiver (rtx);
 360 extern void expand_builtin_longjmp (rtx, rtx);
 361 extern rtx expand_builtin_saveregs (void);
 362 extern void expand_builtin_trap (void);
 363 extern HOST_WIDE_INT get_varargs_alias_set (void);
 364 extern HOST_WIDE_INT get_frame_alias_set (void);
 365 extern void record_base_value (unsigned int, rtx, int);
 366 extern void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT);
 367 extern HOST_WIDE_INT new_alias_set (void);
 368 extern int can_address_p (tree);
 369 \f
 370 /* Functions from expr.c:  */
 371
 372 /* This is run once per compilation to set up which modes can be used
 373    directly in memory and to initialize the block move optab.  */
 374 extern void init_expr_once (void);
 375
 376 /* This is run at the start of compiling a function.  */
 377 extern void init_expr (void);
 378
 379 /* This is run at the end of compiling a function.  */
 380 extern void finish_expr_for_function (void);
 381
 382 /* Use protect_from_queue to convert a QUEUED expression
 383    into something that you can put immediately into an instruction.  */
 384 extern rtx protect_from_queue (rtx, int);
 385
 386 /* Perform all the pending incrementations.  */
 387 extern void emit_queue (void);
 388
 389 /* Tell if something has a queued subexpression.  */
 390 extern int queued_subexp_p (rtx);
 391
 392 /* Emit some rtl insns to move data between rtx's, converting machine modes.
 393    Both modes must be floating or both fixed.  */
 394 extern void convert_move (rtx, rtx, int);
 395
 396 /* Convert an rtx to specified machine mode and return the result.  */
 397 extern rtx convert_to_mode (enum machine_mode, rtx, int);
 398
 399 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 400 extern rtx convert_modes (enum machine_mode, enum machine_mode, rtx, int);
 401
 402 /* Emit code to move a block Y to a block X.  */
 403
 404 enum block_op_methods
 405 {
 406   BLOCK_OP_NORMAL,
 407   BLOCK_OP_NO_LIBCALL,
 408   BLOCK_OP_CALL_PARM
 409 };
 410
 411 extern void init_block_move_fn (const char *);
 412 extern void init_block_clear_fn (const char *);
 413
 414 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 415
 416 /* Copy all or part of a value X into registers starting at REGNO.
 417    The number of registers to be filled is NREGS.  */
 418 extern void move_block_to_reg (int, rtx, int, enum machine_mode);
 419
 420 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 421    The number of registers to be filled is NREGS.  */
 422 extern void move_block_from_reg (int, rtx, int);
 423
 424 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 425 extern rtx gen_group_rtx (rtx);
 426
 427 /* Load a BLKmode value into non-consecutive registers represented by a
 428    PARALLEL.  */
 429 extern void emit_group_load (rtx, rtx, tree, int);
 430
 431 /* Move a non-consecutive group of registers represented by a PARALLEL into
 432    a non-consecutive group of registers represented by a PARALLEL.  */
 433 extern void emit_group_move (rtx, rtx);
 434
 435 /* Store a BLKmode value from non-consecutive registers represented by a
 436    PARALLEL.  */
 437 extern void emit_group_store (rtx, rtx, tree, int);
 438
 439 /* Copy BLKmode object from a set of registers.  */
 440 extern rtx copy_blkmode_from_reg (rtx, rtx, tree);
 441
 442 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 443 extern void use_reg (rtx *, rtx);
 444
 445 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 446    for the next CALL_INSN.  */
 447 extern void use_regs (rtx *, int, int);
 448
 449 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 450 extern void use_group_regs (rtx *, rtx);
 451
 452 /* Write zeros through the storage of OBJECT.
 453    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 454 extern rtx clear_storage (rtx, rtx);
 455
 456 /* Determine whether the LEN bytes can be moved by using several move
 457    instructions.  Return nonzero if a call to move_by_pieces should
 458    succeed.  */
 459 extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 460
 461 /* Return nonzero if it is desirable to store LEN bytes generated by
 462    CONSTFUN with several move instructions by store_by_pieces
 463    function.  CONSTFUNDATA is a pointer which will be passed as argument
 464    in every CONSTFUN call.
 465    ALIGN is maximum alignment we can assume.  */
 466 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 467                                 rtx (*) (void *, HOST_WIDE_INT,
 468                                          enum machine_mode),
 469                                 void *, unsigned int);
 470
 471 /* Generate several move instructions to store LEN bytes generated by
 472    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 473    pointer which will be passed as argument in every CONSTFUN call.
 474    ALIGN is maximum alignment we can assume.
 475    Returns TO + LEN.  */
 476 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT,
 477                             rtx (*) (void *, HOST_WIDE_INT, enum machine_mode),
 478                             void *, unsigned int, int);
 479
 480 /* Emit insns to set X from Y.  */
 481 extern rtx emit_move_insn (rtx, rtx);
 482
 483 /* Emit insns to set X from Y, with no frills.  */
 484 extern rtx emit_move_insn_1 (rtx, rtx);
 485
 486 /* Push a block of length SIZE (perhaps variable)
 487    and return an rtx to address the beginning of the block.  */
 488 extern rtx push_block (rtx, int, int);
 489
 490 /* Generate code to push something onto the stack, given its mode and type.  */
 491 extern void emit_push_insn (rtx, enum machine_mode, tree, rtx, unsigned int,
 492                             int, rtx, int, rtx, rtx, int, rtx);
 493
 494 /* Expand an assignment that stores the value of FROM into TO.  */
 495 extern rtx expand_assignment (tree, tree, int);
 496
 497 /* Generate code for computing expression EXP,
 498    and storing the value into TARGET.
 499    If SUGGEST_REG is nonzero, copy the value through a register
 500    and return that register, if that is possible.  */
 501 extern rtx store_expr (tree, rtx, int);
 502
 503 /* Given an rtx that may include add and multiply operations,
 504    generate them as insns and return a pseudo-reg containing the value.
 505    Useful after calling expand_expr with 1 as sum_ok.  */
 506 extern rtx force_operand (rtx, rtx);
 507
 508 /* Return an object on the placeholder list that matches EXP, a
 509    PLACEHOLDER_EXPR.  An object "matches" if it is of the type of the
 510    PLACEHOLDER_EXPR or a pointer type to it.  For further information, see
 511    tree.def.  If no such object is found, abort.  If PLIST is nonzero, it is
 512    a location which initially points to a starting location in the
 513    placeholder list (zero means start of the list) and where a pointer into
 514    the placeholder list at which the object is found is placed.  */
 515 extern tree find_placeholder (tree, tree *);
 516
 517 /* Generate code for computing expression EXP.
 518    An rtx for the computed value is returned.  The value is never null.
 519    In the case of a void EXP, const0_rtx is returned.  */
 520 #define expand_expr(EXP, TARGET, MODE, MODIFIER) \
 521   expand_expr_real((EXP), (TARGET), (MODE), (MODIFIER), NULL)
 522 extern rtx expand_expr_real (tree, rtx, enum machine_mode,
 523                              enum expand_modifier, rtx *);
 524
 525 /* At the start of a function, record that we have no previously-pushed
 526    arguments waiting to be popped.  */
 527 extern void init_pending_stack_adjust (void);
 528
 529 /* When exiting from function, if safe, clear out any pending stack adjust
 530    so the adjustment won't get done.  */
 531 extern void clear_pending_stack_adjust (void);
 532
 533 /* Pop any previously-pushed arguments that have not been popped yet.  */
 534 extern void do_pending_stack_adjust (void);
 535
 536 /* Return the tree node and offset if a given argument corresponds to
 537    a string constant.  */
 538 extern tree string_constant (tree, tree *);
 539
 540 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.  */
 541 extern void jumpifnot (tree, rtx);
 542
 543 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
 544 extern void jumpif (tree, rtx);
 545
 546 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 547    the result is zero, or IF_TRUE_LABEL if the result is one.  */
 548 extern void do_jump (tree, rtx, rtx);
 549
 550 /* Generate rtl to compare two rtx's, will call emit_cmp_insn.  */
 551 extern rtx compare_from_rtx (rtx, rtx, enum rtx_code, int, enum machine_mode,
 552                              rtx);
 553 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 554                                      enum machine_mode, rtx, rtx, rtx);
 555
 556 /* Two different ways of generating switch statements.  */
 557 extern int try_casesi (tree, tree, tree, tree, rtx, rtx);
 558 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx);
 559
 560 /* Smallest number of adjacent cases before we use a jump table.
 561    XXX Should be a target hook.  */
 562 extern unsigned int case_values_threshold (void);
 563
 564 \f
 565 /* rtl.h and tree.h were included.  */
 566 /* Return an rtx for the size in bytes of the value of an expr.  */
 567 extern rtx expr_size (tree);
 568
 569 /* Return a wide integer for the size in bytes of the value of EXP, or -1
 570    if the size can vary or is larger than an integer.  */
 571 extern HOST_WIDE_INT int_expr_size (tree);
 572
 573 extern rtx lookup_static_chain (tree);
 574
 575 /* Convert a stack slot address ADDR valid in function FNDECL
 576    into an address valid in this function (using a static chain).  */
 577 extern rtx fix_lexical_addr (rtx, tree);
 578
 579 /* Return the address of the trampoline for entering nested fn FUNCTION.  */
 580 extern rtx trampoline_address (tree);
 581
 582 /* Return an rtx that refers to the value returned by a function
 583    in its original home.  This becomes invalid if any more code is emitted.  */
 584 extern rtx hard_function_value (tree, tree, int);
 585
 586 extern rtx prepare_call_address (rtx, tree, rtx *, int, int);
 587
 588 extern rtx expand_call (tree, rtx, int);
 589
 590 #ifdef TREE_CODE
 591 extern rtx expand_shift (enum tree_code, enum machine_mode, rtx, tree, rtx,
 592                          int);
 593 extern rtx expand_divmod (int, enum tree_code, enum machine_mode, rtx, rtx,
 594                           rtx, int);
 595 #endif
 596
 597 extern void locate_and_pad_parm (enum machine_mode, tree, int, int, tree,
 598                                  struct args_size *,
 599                                  struct locate_and_pad_arg_data *);
 600 extern rtx expand_inline_function (tree, tree, rtx, int, tree, rtx);
 601
 602 /* Return the CODE_LABEL rtx for a LABEL_DECL, creating it if necessary.  */
 603 extern rtx label_rtx (tree);
 604
 605 /* As label_rtx, but additionally the label is placed on the forced label
 606    list of its containing function (i.e. it is treated as reachable even
 607    if how is not obvious).  */
 608 extern rtx force_label_rtx (tree);
 609
 610 /* Indicate how an input argument register was promoted.  */
 611 extern rtx promoted_input_arg (unsigned int, enum machine_mode *, int *);
 612
 613 /* Return an rtx like arg but sans any constant terms.
 614    Returns the original rtx if it has no constant terms.
 615    The constant terms are added and stored via a second arg.  */
 616 extern rtx eliminate_constant_term (rtx, rtx *);
 617
 618 /* Convert arg to a valid memory address for specified machine mode,
 619    by emitting insns to perform arithmetic if nec.  */
 620 extern rtx memory_address (enum machine_mode, rtx);
 621
 622 /* Like `memory_address' but pretent `flag_force_addr' is 0.  */
 623 extern rtx memory_address_noforce (enum machine_mode, rtx);
 624
 625 /* Set the alias set of MEM to SET.  */
 626 extern void set_mem_alias_set (rtx, HOST_WIDE_INT);
 627
 628 /* Set the alignment of MEM to ALIGN bits.  */
 629 extern void set_mem_align (rtx, unsigned int);
 630
 631 /* Set the expr for MEM to EXPR.  */
 632 extern void set_mem_expr (rtx, tree);
 633
 634 /* Set the offset for MEM to OFFSET.  */
 635 extern void set_mem_offset (rtx, rtx);
 636
 637 /* Set the size for MEM to SIZE.  */
 638 extern void set_mem_size (rtx, rtx);
 639
 640 /* Return a memory reference like MEMREF, but with its mode changed
 641    to MODE and its address changed to ADDR.
 642    (VOIDmode means don't change the mode.
 643    NULL for ADDR means don't change the address.)  */
 644 extern rtx change_address (rtx, enum machine_mode, rtx);
 645
 646 /* Return a memory reference like MEMREF, but with its mode changed
 647    to MODE and its address offset by OFFSET bytes.  */
 648 #define adjust_address(MEMREF, MODE, OFFSET) \
 649   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1)
 650
 651 /* Likewise, but the reference is not required to be valid.  */
 652 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 653   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1)
 654
 655 /* Return a memory reference like MEMREF, but with its mode changed
 656    to MODE and its address changed to ADDR, which is assumed to be
 657    increased by OFFSET bytes from MEMREF.  */
 658 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 659   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 660
 661 /* Likewise, but the reference is not required to be valid.  */
 662 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 663   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 664
 665 extern rtx adjust_address_1 (rtx, enum machine_mode, HOST_WIDE_INT, int, int);
 666 extern rtx adjust_automodify_address_1 (rtx, enum machine_mode, rtx,
 667                                         HOST_WIDE_INT, int);
 668
 669 /* Return a memory reference like MEMREF, but whose address is changed by
 670    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 671    known to be in OFFSET (possibly 1).  */
 672 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 673
 674 /* Return a memory reference like MEMREF, but with its address changed to
 675    ADDR.  The caller is asserting that the actual piece of memory pointed
 676    to is the same, just the form of the address is being changed, such as
 677    by putting something into a register.  */
 678 extern rtx replace_equiv_address (rtx, rtx);
 679
 680 /* Likewise, but the reference is not required to be valid.  */
 681 extern rtx replace_equiv_address_nv (rtx, rtx);
 682
 683 /* Return a memory reference like MEMREF, but with its mode widened to
 684    MODE and adjusted by OFFSET.  */
 685 extern rtx widen_memory_access (rtx, enum machine_mode, HOST_WIDE_INT);
 686
 687 /* Return a memory reference like MEMREF, but which is known to have a
 688    valid address.  */
 689 extern rtx validize_mem (rtx);
 690
 691 /* Given REF, either a MEM or a REG, and T, either the type of X or
 692    the expression corresponding to REF, set RTX_UNCHANGING_P if
 693    appropriate.  */
 694 extern void maybe_set_unchanging (rtx, tree);
 695
 696 /* Given REF, a MEM, and T, either the type of X or the expression
 697    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 698    if we are making a new object of this type.  */
 699 extern void set_mem_attributes (rtx, tree, int);
 700
 701 /* Similar, except that BITPOS has not yet been applied to REF, so if
 702    we alter MEM_OFFSET according to T then we should subtract BITPOS
 703    expecting that it'll be added back in later.  */
 704 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, HOST_WIDE_INT);
 705
 706 /* Assemble the static constant template for function entry trampolines.  */
 707 extern rtx assemble_trampoline_template (void);
 708
 709 /* Given rtx, return new rtx whose address won't be affected by
 710    any side effects.  It has been copied to a new temporary reg.  */
 711 extern rtx stabilize (rtx);
 712
 713 /* Given an rtx, copy all regs it refers to into new temps
 714    and return a modified copy that refers to the new temps.  */
 715 extern rtx copy_all_regs (rtx);
 716
 717 /* Copy given rtx to a new temp reg and return that.  */
 718 extern rtx copy_to_reg (rtx);
 719
 720 /* Like copy_to_reg but always make the reg Pmode.  */
 721 extern rtx copy_addr_to_reg (rtx);
 722
 723 /* Like copy_to_reg but always make the reg the specified mode MODE.  */
 724 extern rtx copy_to_mode_reg (enum machine_mode, rtx);
 725
 726 /* Copy given rtx to given temp reg and return that.  */
 727 extern rtx copy_to_suggested_reg (rtx, rtx, enum machine_mode);
 728
 729 /* Copy a value to a register if it isn't already a register.
 730    Args are mode (in case value is a constant) and the value.  */
 731 extern rtx force_reg (enum machine_mode, rtx);
 732
 733 /* Return given rtx, copied into a new temp reg if it was in memory.  */
 734 extern rtx force_not_mem (rtx);
 735
 736 /* Return mode and signedness to use when object is promoted.  */
 737 extern enum machine_mode promote_mode (tree, enum machine_mode, int *, int);
 738
 739 /* Remove some bytes from the stack.  An rtx says how many.  */
 740 extern void adjust_stack (rtx);
 741
 742 /* Add some bytes to the stack.  An rtx says how many.  */
 743 extern void anti_adjust_stack (rtx);
 744
 745 /* This enum is used for the following two functions.  */
 746 enum save_level {SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL};
 747
 748 /* Save the stack pointer at the specified level.  */
 749 extern void emit_stack_save (enum save_level, rtx *, rtx);
 750
 751 /* Restore the stack pointer from a save area of the specified level.  */
 752 extern void emit_stack_restore (enum save_level, rtx, rtx);
 753
 754 /* Allocate some space on the stack dynamically and return its address.  An rtx
 755    says how many bytes.  */
 756 extern rtx allocate_dynamic_stack_space (rtx, rtx, int);
 757
 758 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
 759    FIRST is a constant and size is a Pmode RTX.  These are offsets from the
 760    current stack pointer.  STACK_GROWS_DOWNWARD says whether to add or
 761    subtract from the stack.  If SIZE is constant, this is done
 762    with a fixed number of probes.  Otherwise, we must make a loop.  */
 763 extern void probe_stack_range (HOST_WIDE_INT, rtx);
 764
 765 /* Return an rtx that refers to the value returned by a library call
 766    in its original home.  This becomes invalid if any more code is emitted.  */
 767 extern rtx hard_libcall_value (enum machine_mode);
 768
 769 /* Given an rtx, return an rtx for a value rounded up to a multiple
 770    of STACK_BOUNDARY / BITS_PER_UNIT.  */
 771 extern rtx round_push (rtx);
 772
 773 /* Return the mode desired by operand N of a particular bitfield
 774    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
 775    available.  */
 776
 777 enum extraction_pattern { EP_insv, EP_extv, EP_extzv };
 778 extern enum machine_mode
 779 mode_for_extraction (enum extraction_pattern, int);
 780
 781 extern rtx store_bit_field (rtx, unsigned HOST_WIDE_INT,
 782                             unsigned HOST_WIDE_INT, enum machine_mode, rtx,
 783                             HOST_WIDE_INT);
 784 extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
 785                               unsigned HOST_WIDE_INT, int, rtx,
 786                               enum machine_mode, enum machine_mode,
 787                               HOST_WIDE_INT);
 788 extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
 789 extern bool const_mult_add_overflow_p (rtx, rtx, rtx, enum machine_mode, int);
 790 extern rtx expand_mult_add (rtx, rtx, rtx, rtx,enum machine_mode, int);
 791 extern rtx expand_mult_highpart_adjust (enum machine_mode, rtx, rtx, rtx, rtx, int);
 792
 793 extern rtx assemble_static_space (unsigned HOST_WIDE_INT);
 794 extern int safe_from_p (rtx, tree, int);
 795
 796 /* Call this once to initialize the contents of the optabs
 797    appropriately for the current target machine.  */
 798 extern void init_optabs (void);
 799 extern void init_all_optabs (void);
 800
 801 /* Call this to initialize an optab function entry.  */
 802 extern rtx init_one_libfunc (const char *);
 803
 804 extern void do_jump_by_parts_equality_rtx (rtx, rtx, rtx);
 805 extern void do_jump_by_parts_greater_rtx (enum machine_mode, int, rtx, rtx,
 806                                           rtx, rtx);
 807
 808 extern void mark_seen_cases (tree, unsigned char *, HOST_WIDE_INT, int);
 809
 810 extern int vector_mode_valid_p (enum machine_mode);
 811
 812 extern tree placeholder_list;